From DE 10 2004 037 955 A1 there is a known turbo engine with a stator and a rotor, wherein the rotor has rotating blades and the stator has a housing and guide blades. The rotating blades at the rotor side form at least one rotating blade ring, which at one radially outward lying end adjoins a radially inward lying wall of the housing, by which it is surrounded and with which it bounds a radial gap. The radially inward lying wall of the housing is also known as the inner ring or casing ring and serves in particular as the substrate for a run-in coating. Furthermore, from DE 10 2004 037 955 A1 it is known that the gap between the casing ring of the housing and the radially outward lying end of the rotating blade ring or each rotating blade ring can be adjusted or adapted in its size by servomechanisms to provide a so-called Active Clearance Control, so as to automatically influence the gap and ensure an optimal gap maintenance over all operating conditions. According to DE 10 2004 037 955 A1, the radially inward lying housing wall or the casing ring is segmented in the circumferential direction, and preferably each segment is assigned a separate servomechanism. The servomechanisms are preferably electromechanical actuators.
DE 101 17 231 A1 discloses a turbo engine with a stator and a rotor, wherein the gap between radially outward lying ends of the rotating blades and the radially inward lying housing wall can be adjusted by means of a pneumatic, i.e., pressurized air-operated, actuator unit of a rotor gap control module. The pneumatic actuator unit of the rotor gap control module disclosed there has an actuator chamber, a pressure chamber, and valves connecting the actuator chamber and the pressure chamber, and depending on the pressure prevailing in the actuator chamber sealing elements of the rotor gap control module are inflated so as to adjust or adapt the size of the gap between radially outward lying ends of rotating blades and the casing ring of the housing in the sense of a pneumatic Active Clearance Control.
DE 29 22 835 C2 and U.S. Pat. No. 5,211,534 disclose further turbo engines with a pneumatic or pressurized air-operated Active Clearance Control.
Thus, the turbo engine of DE 29 22 835 C2 has a stator and a rotor, while the gap between radially outward lying ends of the rotating blades and an inner ring or casing ring of a housing wall can be pneumatically adjusted. For this, the casing ring is connected to a support ring via flexible sidewalls, with the casing ring, the support ring and the side walls forming a bellows-like structure. By adjusting the pressure in a cavity defined by the bellows-like structure, the gap between radially outward lying ends of the rotating blades and the casing ring can be adjusted. The flexible sidewalls of DE 29 22 835 C2 are curved several times. Accordingly, seen in the axial direction, the sidewalls of DE 29 22 835 C2 curve inward into the cavity for some segments and outward from the cavity for some segments.